Boe INDEX. 
Anterior margin, 10. 
Aplexa hypnorum, 203. 
Arion ater, 69 ; parasites on, 70 ; internal organs of, 2b. 
hortensis, 71 ; jaw of, 7b.; phosphorescent eggs of, 1b. 
Assiminia Grayana, 63 ; teeth of, <b. 
Atax ypsilophora, mite of the Swan mussel, 32. 
AURICULID& (family), 177. 
Avicula margaritifera, pearls of, 28. 
Azeca tridens, 152. 
B. 
BALEA PERVERSA, 164. 
Bithinia Leachii, 57. 
——- tentaculata, 56. 
Bivalves, parts of shell of, 10-13 ; composition and structure 
of shell of, 11; mantle of, 13; digestive organs of, 14 ; 
circulatory apparatus of, 15 ; respiratory organs of, ab. ; 
nervous system of, 17 ; organs of sense of, 7b. ; muscular 
organs of, 2b.; reproduction of, 18; food of, 19; col- 
lecting, 2. 
Branchial opening in bivalves, 14. 
Breadth of shell, 11. 
Bubble snails, 201. 
Bulimus genus, characters and species of, 146. 
acutus, 147. 
— montanus, 148. 
obscurus, 149. 
Byssus, nature of, 21. 
C. 
Cappis-worm case like Valvata piscinalis, 59. 
Cardinal teeth, 12. 
Carychium minimum, 177. 
exiguum, 178. 
Chrysalis snails, 152. 
Circulatory system of bivalves, 15 ; in univalves, 52. 
